1. Field of the Invention
This invention relates to soil separator means of a dishwasher apparatus and in particular to means for comminuting solid soil matter in the dishwashing liquid for improved circulation of the dishwashing liquid during a dishwashing operation.
2. Description of the Background Art
In one form of dishwasher disclosed in U.S. Pat. No. 4,150,680 of Philip P. Johnson et al, which patent is owned by the assignee hereof, an improved structure for separating food soil and the like from the dishwashing liquid is disclosed. The structure is arranged to utilize the combined swirling and longitudinal movement of the dishwashing liquid in the suction passage to the circulation pump for effecting circulation of a portion of the liquid through a soil accumulator having a return passage leading back to the suction portion of the dishwasher liquid circulation means. An impeller is provided in the suction passage for swirling the liquid at relatively high speed to effect the desired transfer of a portion thereof to the soil separating means.
In U.S. Pat. No. 4,168,715 of Raymond W. Spiegel et al, which patent is also owned by the assignee hereof, another form of soil separator is disclosed in a dishwasher structure wherein the soil separating structure is associated with the suction passage leading to the circulation pump. This structure is arranged to utilize the combined swirling and longitudinal movement of the dishwashing liquid in the suction passage produced by a rotary impeller generally similar to that of the above discussed Johnson et al patent. By suitably arranging ports communicating between the suction passage and the separator, the circulation of a portion of the liquid through the separator is automatically effected. More specifically, as disclosed in the Spiegel et al patent, the swirling liquid in the suction passage is urged outwardly from the suction passage through a radially outwardly disposed port and back into the suction passage through a radially inwardly disposed port as a result of the pressure differential resulting from the different radial spacings of the port from the axis of the swirling means.
Another form of soil separator is illustrated in U.S. Pat. No. 1,971,588 of E. S. Stoddard et al. As shown therein, the drain pump is arranged to receive heavier soil particles from the tub sump and force them outwardly into the drain conduit which is normally closed by a valve 91. When the valve is opened, the pump drains the dishwashing machine by pumping the liquid from the bottom portion thereof outwardly through the drain so as to carry with the liquid being drained the soil particles previously delivered to the drain conduit. The drain pump is disposed below the sump, whereas the main liquid circulating impeller is disposed at the bottom wall of the tub.
In U.S. Pat. No. 3,434,671 of Donald S. Cushing et al, a dishwasher pump structure is shown which is provided with an inlet having a grating member including a grid. The size of the openings of the grid are related to the size of the orifices in the spray arm so that particles passing through the grid will pass through the orifices of the spray arms without clogging them. A blade is rotated by the pump adjacent the grating member so as to macerate any food particles trapped thereon until they are small enough to pass through the opening. The blade is pivotally mounted so that if an article is stuck in one of the openings of the grid member, the shaft and projection rotate without damage to either while the blade rides against the obstruction in a reciprocating manner. Where the particle is too large to go through or become lodged in the opening, the blade bats the particle around until it finds its way into a receiving chamber for discharge with the dishwashing liquid when the drain cycle is initiated. The blade preferably does not have a sharpened leading edge, but relies on a small thickness of the edge to macerate the food particles.
Thomas N. Hahn et al, in U.S. Pat. No. 3,981,456, shows another form of food particle macerating means wherein a cutting arm is attached to a helically wound column. The arm is rotated adjacent a grating element. Thus, the cutting arm is capable of riding over or slipping around unmacerable food particles, such as particles of bone, which may become caught in the grid openings. The macerating device is further arranged to dislodge unmacerable particles from the grating element and urge them into a trap for their subsequent collection. In the illustrated embodiment, the macerating device comprises the distal turned end of a helically wound wire.